The project addresses long-term developments in deep well and hard-rock drilling. Researchers in Phase 1 demonstrated that significant improvements in drilling deep, hard rock could be obtained by applying optimal ultra-high (34,000 rev/min) rotational speed on a 0.775-inch diameter core bit (1128 in/sec) average surface speed. The Phase 1 work included a feasibility-of-concept research effort aimed at development and test results that ultimately will result in the ability to reliably drill “faster and deeper,” possibly with rigs having a smaller footprint to be more mobile The principal focus on demonstration-testing of diamond bits rotating at >10,000 rev/min to achieve a high rate of penetration (ROP) with lower inputs of energy and weight-on-bit (WOB) loads.

Phase 2 is a demonstration and testing the ability to extend the Phase 1 results to larger, full-face bits at high rotational speeds less than 10,000 rev/min, but at optimal surface speeds. This effort to scale and extend Phase 1 results will benchmark ultra-high speed performance and development of advanced bits for such high rotational speed applications.

The progression of drilling for the oil and gas industry has required drilling to ever more difficult geological locations. This incorporates drilling to deeper targets through rock made harder by high borehole pressures and confining stresses. Attempting to drill harder rock has resulted in extremely low rates of penetration resulting in additional drilling costs in the several hundreds of millions of dollars.

It has been shown that there is a reduction in mechanical specific energy required to drill when using higher rotation speeds. However, traditional drilling has not extended drilling to rotational speeds above 1000 rpm.

Impact

The significance of an ultra-high-speed drilling system is the ability to drill rock with very low bit weights and specific energy while maintaining and even exceeding conventional penetration rates. This improvement in penetration rates is an opportunity to reduce drilling costs and drastically improve project economics. The estimated annual cost to drill hard rock in North America is in excess of $1.2 billion. The net result for operators is improved profit margin as well as increases in domestic reserves and production.

Accomplishments (most recent listed first)

Phase 1 and 2 testing has been competed. Analysis indicates there is significant promise for improved drilling economics at high rotational speeds.

A summary of the research accomplishments made during the ultra-high speed diamond drilling test program include:

Methods of statistical design of experiments were introduced to provide direction in determine the sequence for bit loading, rotational speed and rock tested for the final series of tests.

More than 100 tests using various rock types and bit types were conducted in Phase 1.

A paper titled “Investigation of Smaller Footprint Drilling System; Ultra-High Rotary Speed Diamond Drilling Has Potential for Reduced Energy Requirements,” authored by Arnis Judzis, et al. (see Judzis, Boucher, McCammon, and Black), was prepared and presented at the IADC/SPE Drilling Conference in February 2006. This paper outlined accomplishments to that time on the Ultra-High Speed Diamond Drilling project.

Statistical analysis of the bench-scale data revealed a general trend to more efficient drilling as rotational speeds increased above approximately 30,000 rpm.

TerraTek met with industry advisors for a Phase 2 kickoff meeting to determine the direction of Phase 2 systems and tests.

Two test concepts were used for Phase 2 testing. The first utilized prototype turbine mud motors and the second high speed hydraulic motors to drive the drill bits. TerraTek’s full-scale drill rig was utilized for the turbine motor tests and a high-speed drilling test stand was engineered and constructed for additional tests.

Various drill bit manufacturers supplied drill bits for high rotational speed drilling. Manufacturers supporting the test program included: ReedHycalog and Hughes Christensen. Drill bits were also supplied by Technology International, Inc. for the mud turbine drilling tests. The turbine motors were supplied by Smith Neyrfor.

(January 2010)
The project formally started July 2003. Phase 1, development of the ultrahigh-speed drilling concept, was completed in June 2006. Phase 2, demonstrations of microhole drilling at ultra-high rotary speeds, were conducted with the help of industry collaborators July 2006 through March 2009. The project is completed.